Multiple die punches with stripper means



W. BREDOW Fig. l

MULTIPLE DIE PUNCHES WITH STRIPPER MEANS Dec. 8, 1964 Filed Aug. 2o,1962 Dec. 8, 1964 w. BREDow 3,160,046

MULTIPLE DIE PUNCHES WITH STRIPPER MEANS Filed Aug. 20, 1962 2Sheets-Sheet 2 Fig.2

United States Patent aimais Mum-"man um nurseries wrrn stemma ift/mansWalter Bretten', Vormaseli 2, Alteld, Germany Filed Aug, 20, 1962, Ser.No. 217,9t- Claims priority, application Germany, Aug. 30, 196i, il65,844 1t? Claims. (Cl. 8313tl) The present invention relates to theequipment of the upper turret plate, especially of multiple die punches,with a controlled centre clamp holder and stripper, the design of whichis such that this centre clamp holder and stripper may adjust itself tovarious gauges of sheet metal to be punched.

According to the invention, there is arranged under the turret plate,and preferably under the upper turret plate, a holding and Astrippingplate, the movement of which precedes that ot the punching tool or toolsand which holds the material in position until the punching tool hasbeen withdrawn from the workpiece. The movement of the holding andstripping plate may be eiiected by the same members which also controlthe movement of the punching tool or tools.

Y In a preferred embodiment of the invention, there is arranged betweenthe upper turret plate and the holding and stripping plate acompressible body or medium in suitable compression cylinders. Suchcompressible bodies are, for example, helical springs, plate springs,annular springs or parts made of rubber.

The invention also relates to the various members required either inorder to t a compressible energy accumulator, or necessary in order tocorrelate the movements of the turret plate and the punching toolson'one hand, and the movement of the holding and stripping plate on theother hand. Y

The invention has the advantage that the holding and stripping membercan adapt itself automatically to various thicknesses of the sheet metalto be punched, and that the material is held down already prior to thepunching and is held in this position until the tool is withdrawn fromthe workpiece. Thus all forces are eliminated which aiect only theitself and its guides and which thus support or accelerate wear of toolsand machine. Furthermore, also the operation is much easier, because theoperator need not observe the behaviour of the workpiece as closely ashitherto.

The invention will be further described, by way of example, withreference to the accompanying drawing, showing two embodiments. in thedrawing:

FIG. 1 is a cross-section of the turret plate, the resilient memberbeing formed by a spring stack located in the guide column ofthe upperturret plate.

FlG. 2 is a further embodiment, in-which the resilient member is locatedbetween the upper turret plate and the holding and stripping plate.

The upper turret plate 1 and the lower turret plate Z are mounted bymeans of their spindles 3 and 4 in the machine frame or tool holder 5.

The upper turret plate 1 contains the displaceable die holder 6,connected in the punching position with the ram 7, and moved therebyduring the punching in a downward direction; during the upward movement,the die holders 6 and the dies l0' and 1li" mounted therein are againwithdrawn from the punched workpiece.

The positively controlled holding and stripping plate 8 is mounted bymeans of its guide column 9 in the spindle 3 of the upper turret plate 1in a displaceable manner. The movement of the holding and strippingplate 3 whereby the same is placed on to the material to be punched, isadvanced relative to the movement ot the r*ICC actual die lil or lil,mounted in the die holder 6. This holding and stripping plate may beoperated, for example, by an eccentric 15 on the driving shaft 25, or alever linkage coupled with the drive 16 for the ram 7. The strippingplate may also be operated pneu'matically or hydraulically. f

The holding and stripping forceis supplied by an energy accumulator 11,for example, a biased stack of plate springs il, iitted into the guidecolumn and so dimensioned that it produces the maximum requiredstripping etfort. v

The eiiect of the springs 11 is caused by the fact'that they are locatedbetween the ram 25 With the head 27 and the guide column, and the ram islocated displaceably in the column 9, whilst the ram pin 2S is guided atits lower end in a recess 29. Y

The parcels of plate springs `11 may also be replaced by other energystorage means, such as helical springs, annular springs, rubber springs,or springs made from rubber-like materials, as well as compressiblegases iu suitable compression cylinders. Y

The energy accumulator may also be located at another point of thetransmission for operating the holding and stripping plate 8. Y Y

This holding and stripping plate 8 acts in that way that, when thepunching process is initiated, the plate advances in front of the dieholder 6 or punch lil or lil so that the actual strippers fitted intothe holding and stripping plate are placed on the material to bemachined. During this movement, the energy accumulator is biased beyondits normal bias. Simultaneously, the die holder 6 with the die lil oritl carries outthe punching. During the upward movement of the dieholder 6 with the die lil or iii, the strippers remain rst on thepunched material until the` spring stack has been destressed to itsnormal bias. Since the holding and stripping plate 8, and the strippersi4 rest under spring action on the punched material, the die iti or itlmay be withdrawn without lifting the workpiece itself.

Since the holding and `stripping plate 8 is not positively connectedthrough the energy accumulator with the actuating mechanism, there areprovided, for example, springs 12, for returning the stripper plate 3 toits loriginal position. The spring bolts i3 simultaneously act as guidepins to secure the stripper plate 8 against rotation relative to theupper turret plate 1.

FIG. 2 shows another solution, embodying the principle of the invention.

The positively controlled holding and stripping plate 8 is also in thiscase located displaceably by means of its guide column 9 in the spindle3 of the upper turret plate i, and also here, the movement whereby thestripper plate 8 is placed on the material to be punched, is advancedrelative to the movement of the die 1d', 19, mounted in the die holder6. However, in this embodiment, the holding and stripping pla-te S ismoved by means of the sloping plane 2l, located on the pull rod 20, -fordriving the ram through a toggle mechanism, whereby the guide column 9is-lifted and lowered.

During the downward movement of the ram 7 for the punching process, theholding and stripping plate 8 also moves towards the workpiece and reststhereon before the actual punching starts. Due to the lateral movementof the pull rod 2) in association with the sloping plane 2li, the guidecolumn 9 of the holding and stripping plate 8 is released for thedownward movement. During the continued downward movement of the ram 7with the die holder 6 and the die lil or lil", the actual punching isperformed. Y

Also here, the holding and stripping force is supplied by energyaccumulators, preferably biased plate spring stacks di, located betweenthe upper turret plate 1 and the holding and stripping plate 8, thecompression of these springs being so dimensioned as to produce themaximum required elort. These plate springs are merely showndiagrammatically.

The stripper plate 3 is secured against twisting relative to the upperturret plate 1 by guide pins 22 which also deline the movement of' theholding and stripping plate S towards the upper turret plate 1.

During the upward movement of the die 16 or lil, the holding andstripping plate 8 with the strippers 14 remainsA on the material untilthe die has been withdrawn against the pressure of the energyaccumulator 41, and only then is the holding and stripping plate Slifted through its guide column 9, by means of the sloping guide plane21 on the pull rod 2li.

The guide plane 21 is so designed and formed that the holding andstripping plate precedes the tool 18 or 10 during the downward movementof the same, and remains on the material during the upward movement ofthe tool lil or 1li until the same has ybeen withdrawn from thematerial.

The action of 'the holding and stripping plate S with tted strippers 14according to the invention corresponds to that of a cutting tool withitted resilient holder and stripper.

The guide plane 21 may cause the vertical movement control of the guidecolumn, for example by means of a roller 32 located at the upper end ofthe guide column 9 and rolling during the actuation of the pull rod 26along the guide plane 21.

What I claim is:

1. Rotary punch press including a frame having upper and lower parts, aspindle supported in the upper frame part, an upper revolving turretplate on the spindle, a lower revolving turret plate coaxiallyjournalled in the lower frame part, a plurality of aligned pairs oftools carried by the plates, the plates being rotatable together tobring a desired pair of tools yto a working position, a stripper andhold-down plate below the upper turret plate, a guide column supportingthe stripper and holddown Vplate and axially slidable in the spindle,means for preventing rotation of the stripper and hold-down platerelative to the upper turret plate, drive means for lowering and raisinga tool carried by the upper turret plate at the working position, andmeans for concurrently lowering and raising the stripper and hold-downplate, the downward motion of the latter plate preceding that of theupper turret plate and the upward motion of the said latter platesucceeding that of the upper turret plate.

2. Rotary punch press including a frame having upper and lower parts, ahollow spindle supported in the upper frame part, an upper revolvingturret plate on the spindle, a lower revolving turret plate coaxiallyjournalled in the lower frame part, a plurality of aligned pairs oftools carried by the turret plates, the turret plates being rotatabletogether to bring a desired pair of tools to a working position, astripper and hold-down plate below the upper turret plate, a guidecolumn supporting the stripper and hold-down plate, the guide columnbeing axially slidable in the spindle, at least one guide pin couplingthe upper turret plate and the stripper and hold-down plate forpreventing relative rotation of the said plates, a plurality ofstripping means on the stripper and holddown plate corresponding to thesaid ltools, drive means for lowering and raising a tool carried by theupper turret plate at the said working position, and means forconcurrently lowering and raising the stripper and holddown plate, thedownward motion of the latter plate preceding that of the upper turretplate and the said latter plate remaining in contact with a workpiecedisposed on the lower turret plate until the tool leaves the workpieceon its upward stroke.

3. Rotary punch press including a frame having upper and lower parts, ahollow spindle supported in the upper frame part, an upper revolvingturret plate on the spin- 4 ldle, a lower revolving turret platecoaxially journalled in the lower frame part, a plurality of alignedpairs of tools carried by the turret plates, the turret plates beingrotatable together to bring a desired pair of tools to a workingposition, a stripper and hold-down plate below the upper turret plate, aguide column supporting the stripper and hold-down plate, the guidecolumn being axially slidable in the spindle, at least one guide pincoupling the upper turret plate and the stripper and holddown plate forpreventing relative rotation of the said plates, a plurality ofstripping means on the stripper and hold-down plate corresponding to thesaid tools, drive means for lowering and raising a tool carried by theupper turret platek at the said working position, and means forconcurrently lowering and raising the stripper and hold-down plate, thedownward motion of the latter plate preceding that of the upper turretplate and the said latter plate remaining in contact with a workpiecedisposed on the lower turret plate until the tool leaves the workpieceon its upward stroke, the said means for raising and lowering the.stripper and punch plate including a rotating shaft forming part of thesaid drive means, an

eccentric on the shaft and acting on the said guide col-` umn to lowerythe stripper and hold-down plate concurrently with a tool at the saidworking position, and resilient means acting between the upper turretplate and the stripper and hold-down plate to bias the plates towardsone another.

4. Rotary punch press as claimed in claim 3, the said guide column beingopen upwardly, and further including a plunger axiallyslidable in theguide column and bearing on the eccentric, and resilient energyaccumulating means disposed between the plunger and the guide column totransmit axial forces therebetween.

k5. Rotary punch press including a frame having upper and lower parts, ahollow spindle supported in the upper frame part, an upper revolvingturret plate on the spindle, a lower revolving turret plate coaxiallyjournalled in the lower frame part, a plurality of aligned pairs oftools carried by the turret plates, the turret plates being rotatabletogether to bring a desired pair of tools to a working position, astripper and hold-down plate below the upper turret plate, a guideVcolumn supporting the stripper and hold-down plate, the guide columnbeing axially slidable in the spindle, at least one guide pin couplingthe upper turret plate and the stripper and hold-down plate for pre,

venting relative rotation of the said plates, a plurality of strippingmeans on the stripper and hold-down plate cor responding to the saidtools, drive means for lowering and raising a tool carried by the upperturret plate at the said working position, and means for concurrentlylowering and raising the stripper and hold-down plate, the downwardmotion of the latter plate preceding that of the upper turret plate andthe said latter plate remaining in contact with a workpiece disposed onthe lower turret plate until the tool leaves the workpiece on its upwardstroke, the said means for lowering and raising the stripper andhold-down plate including a rotating shaft forming part of the saiddrive means, a plunger axially slidable in the upper end of the guidecolumn and projecting therefrom and bearing on the said eccentric,compression spring means disposed between the plunger and the guidecolumn to transmit axial forces therebetween, whereby rotation `of thesaid shaft causes the eccentric to act on the guide column via theplunger to lower the stripper and hold-down plate in advance of thedownward movement of the tool resulting from said rotation.

6. Rotary punch press according to claim 5, including resilient meansacting to bias the stripper and hold-down plate towards the upper turretplate.

7. Rotary punchr press according to claim 6, in which the said resilientmeans consist of springs disposed on the said guide pins.

8. Rotary punch press including a frame having upper and lower parts, ahollow spindle supported in the upper frame part, an upper revolvingturret plate on the spindle, a lower revolving turret platecoaxiallyjournalled in the lower frame part, a plurality of toolscarried by the turret plates and disposed in aligned pairs, means forrotating the turret plates together to bring any pair of tools to aworking position, a rotatable stripper and hold-down plate disposedbelow and coaxially with the upper turret plate, a guide columnsupporting the stripper and holddown plate and axially slidable in thesaid spindle, means for preventing rotation of the stripper andhold-down plate relative to the upper turret plate, a plurality ofstripping means on the stripper and hold-down plate corresponding to thesaid tools, drive means for lowering and raising a tool carried by theupper turret plate at the said working position, a cam moving with thesaid drive means and co-operating with the said guide column to lowerand raise the stripper and holddown plate concurrently with the saidtool, the downward movement of the stripper and hold-down platepreceding that of the tool and the said plate remaining in its loweredposition until after disengagement of the tool from a workpiece disposedon the lower turret plates corresponding tool.

9. Rotary punch press including a frame having upper and lower parts, ahollow spindle supportedrin the upper frame part, an upper revolvingturret plate on the spindle, a lower revolving turret plate coaxiallyjournalled in the lower frame part, a plurality of aligned pairs oftools carried by the turret plates, the turret plates being rotatabletogether to bring a desired pair of tools to a working postion, astripper and hold-down plate below the upper turret plate, a guidecolumn supporting the stripper and hold-down plate, the guide columnbeing axially slidable in the spindle, at least one guide pin couplingthe upper turret plate and the stripper and hold-down plate forpreventing relative rotation of the said plates, a plurality ofstripping means on the stripper and hold-down plate corresponding to thesaid tools, drive means for lowering and raising a tool carried by theupper turret plate at the stroke, the said means for lowering andraising the stripper and hold-down plate including a linearly moving rodforming part of the said drive means, an inclined plane on the said rodacting on the said guide column to lower and raise the stripper andhold-down plate concurrently with the tool motion resulting frommovement of the-rod.

10. Rotary punch press as claimed in claim 9, in which the said drivemeans is a toggle mechanism actuated by the said rod and the saidinclined plane is provided on the upper side of the said rod, the guidecolumn extending upwards to a level above the said plane, and furtherincluding a cam follower on the upper end of the guide column resting onthe said inclined plane, and resilient means disposed'between the upperturret plate and they References Cited by the Examiner UNITED STATESPATENTS 854,706 5/07 Eden 83-132 921,068 5/09 Bertsch et al 83-1351,781,000 11/30 De Beaulieu 83-552 1,940,883 12/33 Rollings 83-5522,168,377 8/39 Wales 83-140 2,268,787 l/42 Wales 83-140 2,329,061 9/43Kopczynski 83-140 2,378,603 6/45 Wales 83-132 2,647,578 8/53 Connor etal. 83-138 2,701,017 2/55 Wiedemann 83-552 2,732,898 1/56 Taylor 831-1372,778,426 1/57 Taylor 83-138 2,805,717 9/57 Taylor 83--139 3,049,0388/62 Friedland 83-552 LEON PEAR, Primary Examiner.

HUNTER C. BOURNE, IR., Examiner.

1. ROTARY PUNCH PRESS INCLUDING A FRAME HAVING UPPER AND LOWER PARTS, ASPINDLE SUPPORTED IN THE UPPER FRAME PART, AN UPPER REVOLVING TURRETPLATE ON THE SPINDLE, A LOWER REVOLVING TURRET PLATE COAXIALLY JOURNALEDIN THE LOWER FRAME PART, A PLURALITY OF ALIGNED PAIRS OF TOOLS CARRIEDBY THE PLATES, THE PLATES BEING ROTATABLE TOGETHER TO BRING A DESIREDPAIR OF TOOLS TO A WORKING POSITION, A STRIPPER AND HOLD-DOWN PLATEBELOW THE UPPER TURRET PLATE, A GUIDE COLUMN SUPPORTING THE STRIPPER ANDHOLD-DOWN PLATE AND AXIALLY SLIDABLE IN THE SPINDLE, MEANS FORPREVENTING ROTATION OF THE STRIPPER AND HOLD-DOWN PLATE RELATIVE TO THEUPPER TURRET PLATE, DRIVE MEANS FOR LOWERING AND RAISING A TOOL CARRIEDBY THE UPPER TURRET PLATE AT THE WORKING POSITION, AND MEANS FORCONCURRENTLY LOWERING AND RAISING THE STRIPPER AND HOLD-DOWN PLATE, THEDOWNWARD MOTION OF THE LATTER PLATE PRECEDING THAT OF THE UPPER TURRETPLATE AND THE UPWARD MOTION OF THE SAID LATTER PLATE SUCCEEDING THAT OFTHE UPPER TURRET PLATE.